The find the missing length of a right triangle we use the Pythagoras theorem that says;
a²=c²-b²,
b²=c²-a² and
c²=a²+b².
Where a and b are the two sides of the triangle and c is the hypotenuse.
Now we are looking for the hypotenuse,
So, c²=a²+b²
=28²+15²
=1009
c = √1009
= 31.765 in
To the nearest tenth,
Answer = 31.8 in